This invention relates to an internal combustion engine and more particularly to an improved cooling arrangement for the cylinder head of such engine.
In overhead valve engines, the intake and/or exhaust passages are formed directly in the cylinder head. Where the engine or cylinder head is liquid cooled, the cylinder head is formed with an internal cooling jacket and the intake and/or exhaust passages are formed by internal walls in the cylinder head around which the cooling jacket extends. However, there are portions of the wall that define the passages which may have larger wall thicknesses, for example, in the area where the valve stems are supported. These thicker wall sections reduce the amount of cooling that is possible for the flow passage.
Where multiple passages are employed for either the intake and/or the exhaust function, it is generally the practice to have the passages formed by a common wall. These common walls provide a substantially greater thickness and thus provide a mass in the interior of the cylinder head which may not be adequately cooled.
In addition, these complex type of internal walls can give rise to pockets where pockets may form, such as either water vapor and/or air, and the cooling of the cylinder head is further deteriorated.
It is, therefore, a principle object of this invention to provide an improved cylinder head cooling arrangement wherein the cooling of the passages in the cylinder head is ensured.
It is a further object of this invention to provide an improved cylinder head arrangement for an internal combustion engine wherein the wall forming the flow passage of the cylinder head is formed with a coolant passage for permitting not only coolant flow but for purging air or water vapor from the cooling jacket and avoiding the formation of pockets that are not filled with liquid coolant.